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Join Date: Nov 2009
Location: Buffalo, NY
Posts: 17
Need Help w hesitation problem

Can anyone assist me with troubleshooting my hesitation. It happens when I take off in first gear or switch to second. Have not really seen any difference in 3rd or 4th. It only happens at low RPMs and the car does not seem to have any different driving characteristics other than this bog or hesitation. A/F ratios seem normal. It is typical CIS 930 with typical mods - turbo, sc cam, IC, ect.
Thanks in Advance,
Chris
Old 11-27-2009, 01:28 PM
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Join Date: Mar 2000
Location: Auburn,In. U.S.A.
Posts: 2,449
Chris,

Might take a look at ignition timing, too much initial advance will make it fall on it's nose a little on low end acceleration sometimes.

Cole
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Cole - 80 930 "The Old Sled"
Mods: TurboKraft Custom IC, 934 Headers, GSX 61, Zork, Port Work, SC Cams, Air Mod Fuel Dist Relocated, Water Meth Injection, BL WUR, MSD 6530, Greddy EBC, Synapse Bov, Short 2nd & 3rd with 8:37 R&P, Wevo Shifter, Coupling, and Mounts, MTX-L SSI-4, Big Brakes, Rebel Coilovers, Bilstein Sports.
Old 11-27-2009, 02:18 PM
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Check the shielded wire that goes to the distributor. It must be the shielded style original wire and not something repaired with normal wire. I saw this recently and the shop spent many hours looking for the problem. This car had a flat spot or hesitation especially noticed in the take off mode in first gear. These two wires go back to the CD box and must be wired with the proper polarity to the distributor, again with the shielded wire.
Old 11-27-2009, 07:26 PM
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Thanks

Thanks for your help.
Old 12-02-2009, 12:54 PM
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If it's not misfiring while hesititaing I'd check the origonally red fabric covered vacuum advance line at it's 4 connection points from the top of the throttle body to the small thermal valve on the breather cover and the distributor advance pot itself. That is if your car has a later USA distributor with the advance and retard pot. The origonal red fabric covered vac advance hose will dry rot and crack under the fabric after 20 years so you can't see a leak in it either so replacing it with a new red silicone vac hose is inexpensive and a good idea.

When these motors don't get any vacuum advance from a dead start all you have is centrifical advance which starts later and advances gradually with rpms.
It's ridiculous how sluggish these cars will be at low speeds without enough ignition advance.

If you don't run a catalytic converter than do your car and yourself a favor and bypass the thermal valve in the vacuum advance line because it's only purpose is to block vacuum advance during cold starts and cold motor running conditions so the ignition timing is retarded causing the exhaust temperature to be higher so the catalytic converter heats up faster.
Old 12-02-2009, 01:17 PM
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